This application is based on and incorporates herein by reference Japanese Patent Application No. 2000-244499.
The present invention relates generally to an electronic control system for controlling a door lock actuator or other similar devices through wireless communication with a communication device such as an electronic key carried by a user of a motor vehicle. More specifically, the present invention relates to an electronic control device that shares one receiver for two types of controls.
Some motor vehicle control systems has a wireless control system by which doors of a vehicle are locked and unlocked from a remote position by manual operation on an electronic key carried by a vehicle user. In this system, the electronic key sends a wireless signal and an electronic control device mounted in the vehicle drives a door actuator to lock or unlock the door in response to the instruction of the wireless signal. The wireless signal includes an identification code specific to the vehicle so that the electronic control device allows the door lock or unlock operation only when the identification code is proper.
Other motor vehicle control systems has a smart control system. In this system, an electronic control device mounted in a motor vehicle detects approaching of a vehicle user carrying an appropriate electronic key and then automatically unlock or lock doors.
When this smart control system determines that conditions requiring confirmation of the presence of an electronic key are satisfied (referred to below as the conditions being true), the electronic control device mounted in the vehicle runs a verification process to authenticate that the electronic key is valid, that is, the electronic key is valid for use with that vehicle. It does this by transmitting a wireless signal from a transmitter and receiving a corresponding response signal from the electronic key through a receiver. It should be noted that in order to improve security, this verification process generally exchanges data with the electronic key plural times.
The electronic key is designed to send a response signal in response to the wireless signal according to predefined rules. If the electronic key is within the range in which the wireless signal from the vehicle can be received, the electronic control device mounted in the vehicle can recognize the presence of the electronic key, that is, the presence of the user carrying the electronic key.
The electronic control device then automatically unlocks the door when it is confirmed that the electronic key is in close proximity to the vehicle by, for example, detecting by a touch sensor whether a user hand has been placed on the external door handle. The electronic control device unlocks the door by controlling the door lock actuator to switch automatically to the unlock position. When a user gets out of the vehicle and the electronic control device detects that a door lock switch disposed beside the external door handle has been pressed, the electronic control device automatically locks the doors by setting the door lock actuator automatically to the lock position.
When a control system providing both the above wireless control and smart control functions is designed, the electronic key carried by the vehicle user operates as a communication device equipped with the functions of both the above electronic keys. The electronic key can be configured to transmit a wireless signal instructing the control device to lock or unlock the door when the user presses a particular button, and to return a response signal to the wireless signal received from the vehicle when the buttons are not operated.
However, the electronic control device in the vehicle must have separate receivers for receiving wireless signals for wireless control and smart entry control from the electronic key. This tends to cause an increase in device size and cost.
It is therefore an object of the present invention to provide an electronic control device which enables a single receiver to be shared for wireless control and a smart control.
According to the present invention, an electronic control system comprises a communication device carried by a user, a receiver for receiving a wireless signal from the communication device, a transmitter for transmitting a wireless signal to the communication device, a wireless control unit for using the receiver to receive an operating signal transmitted from the communication device to operate a specific device such as a door lock actuator of a vehicle, a smart control unit for driving the transmitter to transmit a transmitter signal and using the receiver to receive a response signal from the communication device transmitted in return to the transmitter signal, and automatically controlling the specific device in response to the response signal from the communication device. The system further comprises an arbitration unit for granting a receiver usage privilege to one of the wireless control unit and the smart control unit.
The arbitration unit supplies power to the receiver to operate the receiver if a receiver usage privilege acquisition instruction is output from either one of the wireless control unit and the smart control unit. The arbitration unit assigns a receiver usage privilege to the wireless control unit to enable the wireless control unit to receive data if the receiver received the wireless signal. The arbitration unit assigns the receiver usage privilege to the smart control unit if the receiver did not receive the wireless signal and the smart control unit has output the usage privilege acquisition instruction and stops power supply to the receiver and stops receiver operation, if a receiver usage privilege cancellation instruction is output from one of the wireless control unit and the smart control unit to which the receiver usage privilege has been assigned.